Exam 4: Embryo Implantation

Question 1

What is implantation

Answer 1

When blastocysts come into intimate contact with the endometrium of the uterus

Question 2

Differences in implantation between species

Answer 2

1. Duration of stages
2. Degree of contact
3. Degree of invasiveness

Question 3

5 stages of implanation

Answer 3

1. ZP shedding
2. Pre-contact and blastocyst orientation
3. Apposition
4. Adhesion
5. Penetration of the endometrium

Question 4

Role of progesterone and estrogen in implantation

Answer 4

Prime the uterus which stimulates production of growth factors, other uterine factors such as cytokines and lipid mediators

Question 5

Role of catecholestrogens in implantation

Answer 5

Produced by uterus to stimulate activation of blastocysts to become competent for implantation

Question 6

Role of progesterone receptor in implantation

Answer 6

Must be down-regulated from superficial epithelial layer but not from stroma cells

Question 7

Characteristics of the blastocyst after decidualization

Answer 7

Temporary decidual body
Differentiation and proliferation of stromal fibroblasts under endometrium

Question 8

What compounds may be involved in decidualization

Answer 8

Hoxa-10 genes
Prostaglandins
Histamine
PAF

Question 9

3 functions of decidualized blastocyst

Answer 9

1. Source of nutrients for embryo
2. Stops penetration of trophoblast in animals with invasive type of placentation
3. Creates a buffer zone to protect from an immunological reaction of the mother against the fetus

Question 10

Window of uterine receptivity

Answer 10

1-3 days in primates, hours in rodents

Question 11

Process of uterine receptivity

Answer 11

characteristics of an inflammatory response
alterations in complement pathway, wound repair, immune responses, regulation of coagulation